Apparatus for developing photographic materials

ABSTRACT

A developing unit for photographic materials receives developer from a source via the intermediary of a supplying arrangement. The supplying arrangement dispenses metered quantities of developer and an adjusting arrangement is provided so that these metered quantities can be varied. A sensing arrangement senses the dispensing of the metered quantities and controls the operation of the supplying arrangement.

United States Patent 1191 Merz 1 APPARATUS FOR DEVELOPING PHOTOGRAPHIC MATERIALS Inventor: Werner Merz, Napoleonweg 3,

D-70ll Oberelchingen, Germany Filed: Feb. 12, 1973 Appl. No.: 331,986

[30] Foreign Application Priority Data Feb. 16, 1972 Germany 2207137 US. Cl. 354/324 Int. Cl. G03d 3/02 Field of Search 95/89 R, 93, 96, 97',

[56] References Cited UNITED STATES PATENTS 3,280,716 10/1966 Gall ..95/89R [11] 3,846,818 1451 Nov. 5, 1974 3,491,675 l/l970 Gold 95/89 R 3,517,600 6/1970 Woollacott 95/89 R 3,550,521 12/1970 Carrie 95/93 3,633,487 1/1972 Langkopf 95/89 R Primary Examiner-Fred L. Braun Attorney, Agent, or FirmMichael S. Striker 57 ABSTRACT A developing unit for photographic materials receives developer from a source via the intermediary of a supplying arrangement. The supplying arrangement dispenses metered quantities of developer and an adjusting arrangement is provided so that these metered quantities can be varied. A sensing arrangement senses the dispensing of the metered quantities and controls the operation of the supplying arrangement.

28 Claims, 11 Drawing Figures PATENTEUKBV I914 SHEET 80? 5 FIG. 7

PATENTEDIIIII 5I974 SHEEI 8 OF 5 FIG.6

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PATENTEDNUV 5 I974 SHEEI 5 OF 5 FIG.8

APPARATUS FOR DEVELOPING PHOTOGRAPHIC MATERIALS BACKGROUND OF THE INVENTION The present invention relates to an apparatus for developing of photographic materials, and is particularly advantageous for use in developing of color film.

Apparatus for developing of photographic materials, color films or otherwise, is already well known. Generally such apparatus uses a developing unit in which the photographic materials together with the developer liquid are accommodated. In this unit, the developer liquid is made to contact the photographic material by imparting movement to the unit and thereby to the developer liquid, or in other ways, and this results in the developing of the photographic materials.

One of the problems with the prior art, however, is the fact that such equipment is not always simple to operate and does not have a particularly high throughput which is of course desired.

More importantly, however, it is a disadvantage of the prior art apparatus that the amount of developer admitted into the developer unit can, for various reasons, not be precisely metered. This means that highquality developing of the photographic materials, which depends to a large extent not only on good contact with the developer liquid but also on a rather precise amount of developer liquid, is impossible. It must be remembered here that usually several different liquid components are admitted into such a unit which together constitute the developer liquid, and it is the inability to properly control the ratio of the various components to one another which has been causing problems in the prior art.

SUMMARY OF THE INVENTION Accordingly, it is a general object of the present invention to avoid the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide an improved apparatus of the type in question which is not possessed of these disadvantages.

Still more particularly, it is an object of the present invention to provide such an improved apparatus in which the metering of developer liquid or liquid components admitted into the developer unit is precise and automatic.

Another object of the invention is to provide such an apparatus which is simple in its operation as well as being reliable.

Still, a further object of the invention is to provide such, an apparatus which has a high throughput capacity per unit of time and therefore operates very economically.

In keeping with these objects, and with others which will become apparent hereafter, one feature of the invention resides in an apparatus for developing photographic materials, particularly color films, which, briefly stated, comprises a film developing unit, a source ofdeveloper, and supplying means for supplying metered quantities of developer from the source to the unit. Selecting means is operatively associated with the supplying means for selecting the magnitude of the metered quantities, and sensing means is provided for sensing the developer content in the supplying means and for. controlling the operation of the latter in dependence upon the sensed content and within the magnitude selected by the selecting means.

It is advantageous according to one concept of the invention if one or several heads or containers are provided as part of the supplying means, containing the developer liquid or constituent components of the developer liquid and provided with feelers which extend to different levels within their respective containers and which are part of an electrical circuit which is interrupted when the liquid level in the respective container reaches a certain point which can be preselected by the selection of the respective feeler, for instance interrupting the drive of a pump for pumping the contents into the developer unit. Of course, it is also possible to have the circuit completed under these circumstances.

The feelers themselves are advantageously in form of electrodes which are surrounded in insulated relationship by tubes having open ends which may be beveled to avoid the formation of droplets at these open ends. Also, it is advisable for the insulation which is located in the space between the interior of the tube at the respective electrode to be inwardly offset from the open end of the tube in order to permit the formation of an air bubble in this space, which facilitates proper operation of the circuit, as will be discussed later.

The container or containers communicate of course with the source of supply of the developer liquid, or of the liquid constituent components thereof, and in order to avoid the possibility that the turbulence of incoming liquid might trigger the operation of the circuit, or of the respective circuit do to the formation of waves which might momentarily simulate a liquid level different from the actual level, one or more baffles may be installed in the respective container between the feelers and the inlet openings for the incoming liquid.

It will be appreciated that the containers as well as the unit itself must be flushed at regular intervals in order to remove residual developer liquid or constituent components of such liquid. Insofar as the flushing of the containers is concerned, it is advantageous if the water used for this purpose is admitted into the container or containers in such a manner that it also flushes the inlet openings through which the'developer liquid or component enters the respective container. If more than one inlet opening is provided in a container, then a collecting chamber may be provided interposed in the incoming conduits upstream of the inlet openings, and the flushing water may be admitted into this collecting chamber from which it is distributed to the respective inlet openings. The chamber and portions ofthe incoming conduits are advantageously provided in a cover of the respective container, which cover may be removably accommodated on the container.

The economics of operation of the novel apparatus, and the efficiency thereof, can be further improved if a common flushing system is provided which is common to both the container or containers and the unit. This has the advantage that all components in need of flushing can be flushed readily and efficiently, so that the individual developing processes are not followed by an undesired admixture of various chemical constituents of the developer, and that a change of the ratio of the constituent components of the developer in the unit by the dripping of residual liquid out of one of the containers can be reliably avoided. Also, any residue in the various conduits connecting the components in question can be readily removed in this manner.

As is well known to those skilled in this art, in developer units of the type used in the apparatus according to the present invention there is always the possibility that the outlet provided in the unit may become clogged. This would lead to a backing-up of the developer liquid and/or any flushing water admitted into the unit-and would cause significant problems. Such difficulties can be avoided if, according to a further con cept of the invention, a signal-generating arrangement is provided which operates to generate a signal if the level of liquid in the developer unit is exceeded. In the event this excess level is sensed while the unit contains developer, the generated signal may be used to trigger an increased admission of water in order to prevent an excessive concentration of developer and possible disadvantageous consequences with respect to the film material. In the event the level of liquid is sensed while flushing water is admitted, the signal can be used to direct-partial or complete termination of the admission of flushing water into the unit. In the former case, incidentally, the signal can also be used to interrupt partially or completely the admission of additional developer into the unit. A pump may be provided for pumping out the contents from the unit, and the signal may be used either to turn'on the pump or to speed up the operation of the same. In addition, the same or another signal produced at the same time can be used to produce a warning, for instance to trigger an optical or acoustic warning.

On the other hand, it is desirable that a constant alternating switch switching on and off of the system (the pump, the admission of further liquid or the like) be avoided. For this reason the switching-off of the pump (once the latter has been switched on by the signal), or the admission of liquid flow into the unit will advantageously be permitted only after the level of liquid in the unit has dropped below a preset level which is lower than that at which the triggering was generated.

The control of the flow of liquid into or out of the developer unit itself can also be sensed by an appropriate sensing arrangement, advantageously further feelers which extend to different levels into the liquid reservoir of the unit and which control an electrical circuit, particularly in such a manner that the operation of the liquid-draining pump (or its speeding up), or the shuttingoff of liquid inflow into the developing unit will be triggered only after the level of liquid in the reservoir has dropped below the lowest fecler, it being assumed again that the feeler extends from above and has its lower end atdifferent levels.

It is advantageous if the supplying means with the developer receptacle or receptacles and/or the developing unit itselfpreferably together with the associated conduits and pumpsform a cabinet-like unitary system for'reasons of compactness and neatness of appearance. In such a system the container or containers may for instance be located below the remainder of the supplying means.

As is also well known to those skilled in the art, the quality of the developing work on the film materials, and consequently the quality of the photographs obtained, depends to a substantial extent upon maintaining a certain temperature of the developer liquid. To assure the maintenance of such a temperature a thermostatic arrangement is provided according to the present invention which maintains the temperature of the developer in the single container, or of the various liquid constituents of the developer in several containers, at a preselected level. In addition, an air circulating system may be provided and heating and/or cooling devices and air impellers such as fans or the like which circulates air of desired temperature. The containers, or rather their chemical contents, may be protected against contact with oxygen in a very simple manner, namely by providing floats and/or covers on the containers.

It is also possible according to the invention to provide a programming device which provides for a programmed admission of developer components from the source of supply to the supplying means, for a metering of the components, for a forwarding of the components into the developer unit, and for the removal of the developer from the developer unit, including the admission and removal of flushing water to the supplying means and the developer unit itself. This further improves the economy and efficiency of operation as well as assuring a uniformly high quality of developed film material. A series of control elements, for instance switches or pushbuttons; may be provided by means of which'to select desired programs and to initiate operation of the same, depending upon the requirements of the given circumstances.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic of an apparatus according to the present invention;

FIG. 2 is a diagrammatic longitudinal section through the developer unit of the apparatus;

FIG. 3 is a diagrammatic axial section through a supplying means of the apparatus according to the present invention;

FIG. 4 is a longitudinal section through afeeler'used in the embodiment of FIG. 3;

FIG. 5 is an electrical circuit showing the operation of the supplying means of FIG. 3; I

FIG. 6 is a view similar to FIG. 5 but illustrating th circuitry of the electrical control system for a liquidremoving pump used in the developer unit of FIG. 2;

FIG. 7 is a perspective view of a cabinet, with FIG. 7a illustrating a cabinet for the chemical components of the developer liquid and FIG. 7b illustrating a cabinet console with-the supplying means of FIG. 3;

FIG. 8 is a diagrammatic view of a structural unit containing the constituent components of the apparatus according to the present invention; and

FIG. 9 is a section taken on line 9-9 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing now in detail, it will be seen that FIG. 1 illustrates schematically andin form of an overview an apparatus according to the present invention, showing the connection between the various components. It is preferred, but not necessary, that the apparatus be in form of a unitary assembly such as is shown in FIG. 8.

Reference numeral designates a cabinet containing the source of developer chemicals, namely a plurality of individual tanks 11. There is no need to go into details concerning the particular chemicals; these are well known. Reference numeral 19 designates in toto asupplying means, that is a metering arrangement having a plurality of metering heads or containers 20. In the present embodiment there are two of these containers 20 provided. Conduits 12 and respective branch conduits (two of them are shown) 13 and 14, as well as pumps 15 and 16 and conduits 17 and 18 are provided for supplying chemicals from the tanks 11 to the containers 20. A film developer unit 22 is provided having a developing chamber 23 in which there are located developing devices 24, preferably, but not necessarily, in form of horizontally positioned developing tubes. Supply conduits 21, which may be opened and closed by valves 21a that may be electromagnetically controlled, connect the containers preferably at the lowest points thereof-with the unit 22 so that the chemicalsusually liquids-flow through the conduits 21 into inlet funnels 25 which are connected via conduits 26 with the devices 24.

The exposed film material or photographic material which is to be developed, is located in the tubes of the devices 24 and may for instance be distributed about the inner circumferential surfaces thereof. A drive 24a is provided and, as FIG. 2 shows, it causes the tubes 24 to alternately turn in one direction x and then in the other direction x through a certain portion of arc, so that the photographic material to be developed is made to constantlypass through the developer liquid accommodated in the tubes 24 and filling the same in part. An arrangement 24b may be provided which imparts a longitudinal rocking movement to the tubes 24. 7

Developer liquid becomes spent over a period of use, and the spent liquid is removed from the chamber 23 via a discharge pump 27 and an outlet conduit 28. The pump 27 can be supplemented with a direct discharge conduit 28a through which liquid can be discharged without the use of the pump, and in addition or in place of the conduit 28a there may be an overflow provided at an appropriate level in the lower portion of the chamber 23 or the reservoir 23a thereof in which the developer liquid is accommodated.

In equipment of the type in question it is necessary that the system be flushed periodically in order to remove residual developer chemicals. A flushing system for this purpose, using usually water in accordance with conventional practice, is illustrated in broken lines in FIG. 1 and provided with a supply conduit 29 which maybe connected with a tap or another source of water. A conduit 30 branches off the conduit 29 through each of the container units or devices 24 with whose inlet funnels 25 they communicate via valves 32 and conduits 33. Additional branch conduits 31 branch off the conduit 29 and communicate with the respective containers 20 via valves 34 and conduits 35. ()vertlow conduits 36 are provided which prevent the liquids, that is chemicals or flushing water, from exceeding a certain level in the containers 20. Advantageously these overflow conduits are connected with the containers 20 at the highest point of the interior 20a thereof so that the entire height of the respective con- 6 tainer 20 can be used for accommodating liquid to be metered.

Referring now to FIGS. 3-5, it will be seen that in these figures l have illustrated details of the supplying means 19. The illustrated container 20 has a hollow, preferably removable, cover 37, the hollow interior 38 of which can serve as a collector for the flushing water which is admitted via the conduit 35. The inletconduits 17 for the developer chemical or chemicals extend in part through the space or chamber 38, such parts being identified with reference numeral 39 and having the outlet openings which communicate with the interior 20a. Conduits 17 are bent in a downward curve as close as possible above the upper side of the cover 37, extending downwardly to the pumps 15 and 16; the purpose of this is to assure that in the event the supply of liquid through these conduits is interrupted, only a relatively small amount of liquid remains in the conduits in those portions thereof from which it can flow into the container 20.

Annular openings 38a, surrounding the outlet openings of the portions 39, establish a communication between the space 38 and the interior 20a of the respective container 20. The purpose of this is to assure that the flushing water which is discharged into the space 38, whether under pressure or not, will enter directly into the outlet openings of the conduits 17 and thus flush these outlet openings before it enters the interior 20a of the container 20. A valve 21a is provided which controls the connection of the interior 20a with the unit 23 via the conduit 21. A solenoid or similar device is provided which controls the opening and closing of this valve, advantageously automatically in dependence upon a preselected program as will be discussed later.

The space 20a is subdivided by a baffle 41 into an inlet compartment 42 into which liquid is discharged by the conduits 17 from above, and into a sensing compartment 43 locating with the compartment 42 and into which the individual feelers 44 of the sensing system extend from above to different depths. Also there is provided a counter electrode 45 serving as a counter pole to the feelers 44. it is advantageous if the feelers 44 and the electrode 45 are mounted in the cover 37, advantageously in such a manner that they can be removed with the cover and then be removed from the same. The number of feelers 44 to be provided can be selected at will, so that the metering can be very precisely controlled, depending upon the number of feelers. The latter can also be made adjustable so that they can be inserted to greater or lesser depths in the container 20, permitting a precise height adjustment of their contacts 46 within the container 20.

It will be appreciated that the illustrated arrangement of the feelers 44 is exemplary only. They can also be arranged in other ways as long as it is assured that their contacts 46 are located at different levels within the compartment 43 so that the liquid level 47 rising in the compartment 43 will reach the individual contacts 46 of the various feelers 44 at different times. The electrode 45 extends over a height which corresponds at least to the difference between the highest and lowest contact 46.

One of the feelers 44 is illustrated on an enlarged scale in a longitudinal section in FIG. 4. It will be seen to have an interior electrode 48 which may, for instance, be of special steel, the lower free end of which forms the contact 46. The electrode 48 is located within a tube 49 surrounding it with spacing, and in the space between them is insulating material 50, for instance a polyester resin or the like. The lower end of the tube 49 is open and surrounds the contact 46 to a greater or lesser degree. It is also beveled at 51, the purpose being to prevent the formation of drops at the lower end in the event the liquid level 47 descends below the level at which the contact 46 is located. It is also advantageous if, as shown in FIG. 4, the insulating material 50 is upwardly recessed from the contact 46 to assure that in thelower region of the tube 46 an air bubble 52 can be formed, preventing electrical shorting between the contact 46 to the liquid at the wall of the tube.

FIG. shows a circuit diagram for the supplying means. The electrodes 48 with the contacts 46 of the feelers 44 (the latter are not shown) extend into the compartment 43, together with the electrode 45, all of them from above. Electrical energy is supplied at 53, for instance representative of a source supplying alternating current at 220 volts, although this is of course only exemplary. The motor 54 is energized by the source of drive 1 of the pumps or 16. If desired, individual motors can be provided .for each of the pumps, or motors 54 can be utilized which drive the pumps l5, 16 in groups or together in which latter case, however, special circuitry would have to be providedso that a pump selected for individual operation in accordance with a program could be driven alone or in conjunction with other individually selected pumps, whereas the remaining pumps would not be driven or would not supply liquid to the supplying means.

Switch 55 in the circuit-56 of the motor 54 can be 0perated to be switched on and off by a relay 57, so as to energize. and deenergize the motor 54. The relay 57 is positioned in a low-voltage circuit 58 which includes the secondary side of a transformer 59 but is also connected with the source 53. A conductor of the circuit 58 is connected with the counter electrode which may, for instance, constitute the negative pole of the circuit 58, and the conductor extends to individual contacts 60 which can be electrically connected with the electrodes 48 via individual switches 61.

If one of the switches 61, for instance the one that is designated with reference numeral 61a, is moved to closed position 61a manually or automatically, and if the compartment 43 is empty, then the circuit 58 remains interrupted. This interruption continues even while liquid (for instance one of the chemicals from one of the tanks 11) is admitted into the container 20, as long as the level of liquid remains below that of the contact 460 that has been selected with the switch 61a. However, as soon as the level It is reached at which the liquid wets the contact 46a, the circuit between the counter electrode 45 and the contact 46 is closed, causing the relay 57 to open the switch and to deenergize the motor 54. This in turn results in deenergization of the pump 15 or 16 driven by the motor 54 and in a termination of the supply of liquid via the associated con duit 17 into the container 20.

Referring now to FIG. 2, it will be seen that here there is illustrated an arrangement 62 which has been diagrammatically shown in FIG. 2 also, and which is accommodated in the lower reservoir compartment 23a of the chamber 23 with which the outlet conduits 28 and 28a (the former with the pump 27) are in communication. The arrangement 62 may be used to switch on the pump 27, or to cause it to speed up operation, or

again to close or partially close a valve in one of the conduits leading to the chamber 23, for instance the valve 32 in the conduit 33 (see FIG. 1) or a valve in the conduit 2l-through which a mixture of flushing water and spent developer liquid is discharged during the flushing operation. This is to take place as soon as the level of liquid in the reservoir 23c reaches a certain predetermined level, the purpose to be sure that overflowing of the compartment 23 by liquid issuing from the conduit or conduits 33 and/or the conduit or conduits 21 is prevented.

In FIG. 6, reference numeral 53 is again representative of the source of electrical supply, reference numeral 63 designates a transformer the primary side of which is connected with the source 53. A circuit 64 connected with the source 53 also includes the motor 65 of the pump 27, which can be energized or deenergized by a switch 66 closing the motor circuit. Conductors 67 and 68 are connected with the secondary side of the transformer 63 and the conductor 67 extends to an electrode 69 acting as a feeler and which may for instance be a negative electrode, whereas at the conductor 68 with its branch conductor 68a and 68b is electrically connected with two additional feeler electrodes 70 and 71 which may be positive if the electrode 69 is negative. The electrodes have contacts 72, 73 and 74, respectively, which extend from above to different levels into the reservoir 23a. A relay 75 provides for a connection of the circuit with the electrodes 70 and 71, and via a switch 76 arranged after the relay 75 with the electrode 70. If the switch 76 is closed, the electrode 70 is connected with the conductor 68.

A further conductor 68c extends to a third positive feeler electrode 78 having a contact 79. A relay 77 is interposed in the conductor 680. FIG. 6 indicates that the contacts 72, 73 74 and 79 are located at different levelsin the reservoir. A switch 80 interposed in a circuit 81 is activated by relay 77, and the circuit may be utilized to for instance energize or deenergize a magnet 82 of a magnet valve 32 in the conduit 33, as well as to activate or deactivate a switch 83 in a circuit 84 which triggers a warning signal 85. r

As long as, with this arrangement, the level of liquid in the reservoir 23a is below the contact 73, the circuit which in FIG. 6 is connected via the transformer 63 to the source 53 is without current, because the current path between the negative contact 72 and the positive contact 73, 74 and 79 is interrupted. Only the valve 32 is connected via switch 80 and circuit 81 to the supply 53'and is in open condition, so that flushing water can freely enter-for instance via the conduit 33into the chamber 23.

When the level of liquid reaches the contact 73, the circuit continues to remain interrupted because the switch 76 is open. However, when the level of liquid has risen to reach the contact 74, then the circuit between the contacts 72 and 74 will be completed and relay 75 will become energized to close the switch 66 and the switch 76. Closing the switch 66 causes the motor 65 of the pump 27 to become energized. so that a the pump pumps liquid out of the reservoir 23a with the result that the level therein will drop. On' the other hand, the switch 76 was closed at the same time switch 66 was closed, and this closed the circuit for the electrode 70 having the contact 73, so that even after the level of liquid drops below the level of the contact 74, a circuit remains completed between the contacts 72 and 73. As a result of this the pump 27 will continue to operate even after the level of liquid drops below the contact 74; and in fact until the level of liquid drops below the contact 73. Only then will the pump be cleanergized, and this delay has been incorporated in the construction to prevent constant alternating switching on-and off of the pump 27 as soon as the level of liquid exceeds or drops below the contact 74.

Of course, malfunctions in the operation of the pump 27 can occur, or the inflow of liquid can be so substantialthat the pump 27 might not be able to cope with it. Many case, the level of liquid in the reservoir 23 would continue to rise despite the operation of the pump 27 (or with the pump 27 being inoperative) above the contact 74. If this takes place, and the level finally rises to the contact 79, the circuit via the latter is completed, causing the relay 77 to open the switch 80 and to close the switch 83. Opening of the switch 80 results in closing of the valve 32 in the inflow conduit 33 for flushing water. Closing of the switch 83 activates a warning signal 85, for instance an optical or an acoustical signal which indicates that the outflow of liquid from the reservoir 23a does not take place properly and that there is a danger that overflowing might occur. This will then result in alerting the operator to the'fact that necessary corrective measures must be taken at once.

Coming now to FIG. 7, it will be seen that in the portion 70 thereof there is shown the console with the tanks 11, the pumps and 16 and the conduit 17. The front wall of the console and one of the side walls 86 have been shown partially removed for the sake of clarity. An upper portion 87 (shown in FIG. 7b) can be placed atop the console 10 and contains the supplying means 19 with the containers 20. All control elements necessary for controlling the operation ofthe apparatus are mounted at the front wall of the console, including a program control device 88 which can accept a control card 89 on which the computer program for the program-controlled operation of the apparatus may be encoded, for instance in form of punches, magnetically or otherwise. A series 90 of switches, for instance pushbutton switches, permits a selection of the metered quantities of chemicals, by selecting the respective feeler 44 in response to depressing of the appropriate switch.

FIGS. 8 and 9, finally, show an assembly according to the present invention, that is a construction in which all of the constituent components of the apparatus are combined in a unitary assembly. Reference numerals 10, ll, 88 and 90 designate the components previously discussed. The upper portion 87 of the assembly accommodates the components 88 and 90. A unit 9i is placed onto the right-hand compartment on the righthand console 10 and may also serve to accommodate tanks 11. Two pivotable overflow tubes 21 are provided which can discharge into the (not illustrated in FIG-8) inlet funnels which supply the metered chemicals into the units 24 located in a console 92 surrounding the developing chamber 23.

It is advantageous to provide an air circulation system circulating the air as indicated by the arrows, and for instance a ventilator, fan or the like can be used for this purpose. It is well known that the temperature of the developer chemicals should be controlled as closely as possible to obtain the best developing results. The

Ill

ventilator 93 serves the purpose of circulating the air through the console or consoles 10 to maintain the temperature therein as constant as possible. Channels are provided between the tanks and the walls ofthe console or consoles Ill and a channel94 connects these with the ventilator 93' so that the latter can passair around the tanks 11. A heating device 95 and a cooling device 96, both well known in the art, can be provided. A compressor 97 serves to remove heat from the cooling device 96. A thermostat 98 is provided sensing the temperature in the console or consoles 10 and controlling the operation of the devices 93, 95 and 96in order to maintain the desired temperature constant. In the lower portion of the console or consoles 10 there will be provided a drip pan 100 which can receive condensation. A timer 900 can be connected into the circuit in order to vary the programmed control times. An individual tank 11 is shown in diagrammatic section in the upper portion 91 shown in FIG. 1, and the liquid chemicals in the tank 11 are designated with reference numeral 11a. A float 101 is provided which prevents the entry of air to the chemicals, because this could result in deterioration of the chemicals. A dust cover 102 is provided which prevents the entry of dust or other contaminants into the interior of the tank 11.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of constructions differing from the type described above.

While the invention as been illustrated and described as embodied in an apparatus for developing of photographic materials, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer; supplying means for supplying metered quantities of developer from said source to said unit; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means; and signal-generating means for generating a control signal for controlling the inflow of medium into said unit in response to the contents of said unit exceeding a predetermined level, and for also generating a warning signal at least substantially simultaneously with said control signal.

2. A combination as defined in claim 1, said supplying means comprising at least one container and communicating with said unit for permitting the flow of developer to the latter; and wherein said sensing means comprises electric circuit means including two feelers extending into said container and, each having a free end located at a different predetermined level therein, said electric circuit means being operative for interrupting the flow of developer to said unit in response to the level of developer in said container reaching one of said free ends.

3. A combination as defined in claim 2, said circuit means including a source of electrical energy, each of said feelers being connected with one pole of said source of electrical energy; and wherein said circuit means further includes an electrode in said container connected with the other pole of said source of electrical energy and having a free end portion located at least at the lowest of said predetermined levels.

4. A combination as defined in claim 2, said container having inlet means communicating with same; and further comprising a'baffle interposed between said inlet means and said feelers for shielding the latter against the turbulence of incoming developer.

A combination as defined in claim 2, said container having an upper end; and wherein said feelers extend downwardly in said container from said upper end.

6. A combination as defined in claim 2, said container having a lowest portion provided with an outlet; further comprising a normally closed valve in said outlet; and operating means for opening said valve.

7. A combination as defined in claim 6, wherein said operating means comprises an electromagnet controlled by said sensing means.

8. A combination as defined in claim 6, and further comprising a flushing system common to said supplying means and said unit for flushing developer from the same.

9. A combination as defined in claim 4, said unit being located at a level lower than said supplying to said supplying means and said unit.

11. A combination as defined in claim 10, said programming means including switching means operative for selecting different programs.

12. A combination as defined in claim 10, further comprising a console accommodating said source, supplying means and unit; and wherein said programming means is carried by said console.

13. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer; supplying means for supplying metered quantities of developer from said source to said unit; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means; and signal-generating means for generating a control signal for controlling the inflow of medium into said unit in response to the contents of said unit' exceeding a predetermined level, said unit having areser-' voir for said developer, and said signal-generating" means being at least in part located in said reservoir.

14. A combination as defined in claim 13; and further comprising a pump controlled by said control signal for removing contents from said unit in response to generation of said control signal.

15. A combination as defined in claim 13, and further comprising a pump controlled by said control signal for removing contents from said unit'in response to generation of said control signal and at least until the level of contents has dropped below said predetermined level.

16. A combination as defined in claim 15, said signalgenerating means comprising an electric circuit and a plurality of electrode members connected in said circuit and having free ends located at different levels in said reservoir.

17.. A combination as defined in claim 13, said unit having a reservoir for said developer; further comprising a pump for removing the contents of said reservoir from the same at least in part and at least when such contents exceed a predetermined level.

18. A combination as defined in claim 13, wherein said source, supplying means and/or unit together form a cabinet-shaped structural assembly.

19. A combination as defined in claim 18, wherein said source is located in a top portion and said supplying means is located in a bottom portion of said assembly.

20. A combination as defined in claim 18, further comprising thermostatically controlled means operative for maintaining the temperature of at least said source at a preset level.

21. A combination as defined in claim 20, said thermostatically controlled means comprising heatexchange means.

22. A combination as defined in claim 21, said thermostatically means further comprising circulating means for circulating air in contact with at least said source.

23. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer; supplying means for supplying metered quantities of developer from said source to said unit, said supplying means comprising at least one container and communicating with said unit for permitting flow of developer to the latter; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; and sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means, said sensing means comprising electric circuit means including two feelers extending into said container and each having a free end located at a different predetermined level therein, said feelers each including a conductive electrode member and a'tubular member surrounding said electrode member electrically insulated therefrom and having a bevelled tip, and said circuit means being operative for interrupting the flow of developer to said unit in response to the level of developer in said container reaching one of said free ends.

24. A combination as defined in claim 23, wherein said feelers are carried by a cover of said container.

25. A combination as defined in claim 23, said container having an upper end portion; and further comprising an overflow opening provided in said upper end portion for overflowing of water used to flush developer from said container.

26. A combination as defined in claim 23, said tubular members being open at said tip; and wherein each of said feelers includes electrically insulating means interposed between the respectively associated tubular and electrode members and terminating inwardly of the respective open bevelled tip.

27. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer, including a reservoir; supplying means for supplying metered quantities of developer from said source to said unit; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means; a pump; and signal-generating means for generating a control signal for controlling the inflow of medium into said unit in response to the contents of said unit exceeding a predetermined level, said signal-generating means controlling said pump so that the latter removes contents from said unit in response to generation of said control signal and at least until the level of contents has dropped below said predetermined level, said signal-generating means comprising an electric circuit and a plurality of electrode members connected in said circuit and having free ends located at different levels in said reservoir for said developer, including a first electrode member having its free end located at the highest level to which liquid is to rise in said reservoir and operative for terminating inflow of liquid into said reservoir in response to the contents therein reaching its free end, a second electrode member having its free end located at a lower level, and a third electrode member having its free end located at an intermediate level and connected with said second electrode member in such a manner as to initiate operation of at least said pump when the level of contents reaches said free end of said third electrode member and continue the initiated operation at least until such level drops below said free end of said third electrode member.

28. A combination as defined in claim 27, said supplying means further comprising a container, at least one conduit communicating with an upper end of said container, and having an outlet portion provided with a discharge opening directed into said container, a conduit portion extending downwardly of said upper end outside said container, and a bend portion connecting said outlet portion and said conduit portion; said pump being interposed in said conduit portion. 

1. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer; supplying means for supplying metered quantities of developer from said source to said unit; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means; and signalgenerating means for generating a control signal for controlling the inflow of medium into said unit in response to the contents of said unit exceeding a predetermined level, and for also generating a warning signal at least substantially simultaneously with said control signal.
 2. A combination as defined in claim 1, said supplying means comprising at least one container and communicating with said unit for permitting the flow of developer to the latter; and wherein said sensing means comprises electric circuit means including two feelers extending into said container and each having a free end located at a different predetermined level therein, said electric circuit means being operative for interrupting the flow of developer to said unit in response to the level of developer in said container reaching One of said free ends.
 3. A combination as defined in claim 2, said circuit means including a source of electrical energy, each of said feelers being connected with one pole of said source of electrical energy; and wherein said circuit means further includes an electrode in said container connected with the other pole of said source of electrical energy and having a free end portion located at least at the lowest of said predetermined levels.
 4. A combination as defined in claim 2, said container having inlet means communicating with same; and further comprising a baffle interposed between said inlet means and said feelers for shielding the latter against the turbulence of incoming developer.
 5. A combination as defined in claim 2, said container having an upper end; and wherein said feelers extend downwardly in said container from said upper end.
 6. A combination as defined in claim 2, said container having a lowest portion provided with an outlet; further comprising a normally closed valve in said outlet; and operating means for opening said valve.
 7. A combination as defined in claim 6, wherein said operating means comprises an electromagnet controlled by said sensing means.
 8. A combination as defined in claim 6, and further comprising a flushing system common to said supplying means and said unit for flushing developer from the same.
 9. A combination as defined in claim 4, said unit being located at a level lower than said supplying means and having at least one inlet funnel; and wherein said supplying means comprises at least one outlet conduit for said developer to and from a position in which it in fluid communication with said inlet funnel.
 10. A combination as defined in claim 1, further comprising programming means for programmed control of the supply of developer to said supplying means from said source, supply of said metered quantities to said unit, and admission and removal of flushing water to said supplying means and said unit.
 11. A combination as defined in claim 10, said programming means including switching means operative for selecting different programs.
 12. A combination as defined in claim 10, further comprising a console accommodating said source, supplying means and unit; and wherein said programming means is carried by said console.
 13. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer; supplying means for supplying metered quantities of developer from said source to said unit; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means; and signal-generating means for generating a control signal for controlling the inflow of medium into said unit in response to the contents of said unit exceeding a predetermined level, said unit having a reservoir for said developer, and said signal-generating means being at least in part located in said reservoir.
 14. A combination as defined in claim 13; and further comprising a pump controlled by said control signal for removing contents from said unit in response to generation of said control signal.
 15. A combination as defined in claim 13, and further comprising a pump controlled by said control signal for removing contents from said unit in response to generation of said control signal and at least until the level of contents has dropped below said predetermined level.
 16. A combination as defined in claim 15, said signal-generating means comprising an electric circuit and a plurality of electrode members connected in said circuit and having free ends located at different levels in said reservoir.
 17. A combination as defined in claim 13, said unit having a reservoir for said developer; further comprising a pump for removing the contents of said reservoir from the same at least in part and at least when such contents exceed a predetermined level.
 18. A combination as defined in claim 13, wherein said source, supplying means and/or unit together form a cabinet-shaped structural assembly.
 19. A combination as defined in claim 18, wherein said source is located in a top portion and said supplying means is located in a bottom portion of said assembly.
 20. A combination as defined in claim 18, further comprising thermostatically controlled means operative for maintaining the temperature of at least said source at a preset level.
 21. A combination as defined in claim 20, said thermostatically controlled means comprising heat-exchange means.
 22. A combination as defined in claim 21, said thermostatically means further comprising circulating means for circulating air in contact with at least said source.
 23. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer; supplying means for supplying metered quantities of developer from said source to said unit, said supplying means comprising at least one container and communicating with said unit for permitting flow of developer to the latter; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; and sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means, said sensing means comprising electric circuit means including two feelers extending into said container and each having a free end located at a different predetermined level therein, said feelers each including a conductive electrode member and a tubular member surrounding said electrode member electrically insulated therefrom and having a bevelled tip, and said circuit means being operative for interrupting the flow of developer to said unit in response to the level of developer in said container reaching one of said free ends.
 24. A combination as defined in claim 23, wherein said feelers are carried by a cover of said container.
 25. A combination as defined in claim 23, said container having an upper end portion; and further comprising an overflow opening provided in said upper end portion for overflowing of water used to flush developer from said container.
 26. A combination as defined in claim 23, said tubular members being open at said tip; and wherein each of said feelers includes electrically insulating means interposed between the respectively associated tubular and electrode members and terminating inwardly of the respective open bevelled tip.
 27. In an apparatus for developing photographic materials, particularly color films, a combination comprising a film developing unit; a source of developer, including a reservoir; supplying means for supplying metered quantities of developer from said source to said unit; selecting means operatively associated with said supplying means for selecting the magnitude of said metered quantities; sensing means for sensing the developer content in said supplying means and for controlling operation of said supplying means in dependence upon the sensed content and within the magnitude selected by said selecting means; a pump; and signal-generating means for generating a control signal for controlling the inflow of medium into said unit in response to the contents of said unit exceeding a predetermined level, said signal-generating means controlling said pump so that the latter removes contents from said unit in response to generation of said control signal and at least until the level of contents has dropped below said predetermined level, said signal-generating means comprising an electric circuit and a plurality of electrode members connected in saiD circuit and having free ends located at different levels in said reservoir for said developer, including a first electrode member having its free end located at the highest level to which liquid is to rise in said reservoir and operative for terminating inflow of liquid into said reservoir in response to the contents therein reaching its free end, a second electrode member having its free end located at a lower level, and a third electrode member having its free end located at an intermediate level and connected with said second electrode member in such a manner as to initiate operation of at least said pump when the level of contents reaches said free end of said third electrode member and continue the initiated operation at least until such level drops below said free end of said third electrode member.
 28. A combination as defined in claim 27, said supplying means further comprising a container, at least one conduit communicating with an upper end of said container, and having an outlet portion provided with a discharge opening directed into said container, a conduit portion extending downwardly of said upper end outside said container, and a bend portion connecting said outlet portion and said conduit portion; said pump being interposed in said conduit portion. 